Field of the Invention
The present invention relates to method and system for controlling a start of a fuel cell to control a cold start driving mode using a heat value of the fuel cell even though a coolant pump is not driven.
Description of the Related Art
In general, a fuel cell generates electricity using an electrochemical reaction of hydrogen as fuel and oxygen in the air and discharges heat and water as reaction by-products. Further, water remaining in a stack of a fuel cell may be frozen in a fuel cell vehicle including the fuel cell such as a proton exchange membrane fuel cell (PEMFC) used as a power source in an atmospheric condition below zero temperatures when the vehicle is parked over a long period of time in winter or colder weather, thus significantly reducing cold start performance.
Therefore, there is a difficulty in a next cold start due to freezing of water when the water remaining in the stack is not removed or discharged when a vehicle is turned off at low atmospheric temperatures. In other words, when the fuel cell is started while ice formed in the stack is not melted, ice hinders hydrogen and air supply paths to cause start inferiority and disturb normal operation of the fuel cell.
Therefore, various methods of controlling a cold start of the fuel cell have been proposed to prevent a flooding phenomenon. For example, one method of the related art includes supplying current only in an amount to prevent water formed in a fuel cell from being frozen and thus secure start reliability of the fuel cell during the cold start. However, in the related art, an air temperature sensor disposed at an air outlet of a stack is used to detect an internal temperature of the stack. The internal temperature of the stack may be indirectly reflected using the air temperature sensor at the air outlet when a flow rate of air is high and thus a heat capacity of air is large, but when the flow rate of air is low or severely changed, it may be difficult to indirectly reflect the internal temperature of the stack, and air may be rapidly cooled in a common distribution structure after the air is discharged from the stack, accordingly, an increase in internal temperature is not reflected.
The foregoing is intended merely to aid in the understanding of the background of the present invention, and is not intended to mean that the present invention falls within the purview of the related art that is already known to those skilled in the art.